中文摘要：

胡杨（Populus euphratica Oliv.）具有极强抗盐碱能力.本实验室前期胡杨微阵列芯片数据结果显示：盐胁迫下,胡杨谷胱甘肽过氧化物酶基因（PeGPX）的转录上调,暗示该基因可能对胡杨耐盐性具有一定的作用.为分析GPX对植物耐盐性的贡献,本研究以胡杨为材料,利用RT-PCR方法克隆了胡杨谷胱甘肽过氧化物酶PeGPX基因,并在烟草中过量表达该基因,以分析谷胱甘肽过氧化物酶活性与植物耐盐性的关系.研究结果显示,实验中克隆的cDNA （PeGPX）编码谷胱甘肽过氧化物酶,其ORF为693 bp,其蛋白由231个氨基酸编码.过量表达PeGPX基因的烟草与野生型烟草的耐盐性实验结果显示,野生型烟草植株在加NaCl （200 mmol/L）的MS培养基中生长15 d后,无明显的长高,且不长根;而转基因烟草在同样的加盐培养基上,生长基本没有受到抑制,植株生长状态良好,并且能够长根.光合数据显示,在盐胁迫下过量表达PeGPX基因烟草的净光合速率受到影响明显小于野生型烟草的净光合速率.酶活数据显示,转基因株系GPX酶活与野生型的相比在盐胁迫下活性有非常显著的提高.我们的研究结果说明：过表达PeGPX基因使得烟草的耐盐性得到显著提高,这对深入研究PeGPX基因在胡杨耐盐机制中的作用具有重要的意义.

英文摘要：

Popuhts euphratica has a high capacity to tolerate salinity. Previous transcriptomic analysis of P. euphratica shows that glutathione peroxidase gene （PeGPX） is up-regulated under salt stress. That indicates PeGPX enzyme may play an important role in salt tolerance ofP. euphratica. To analyze the functions of PeGPX in salinity tolerance, we cloned the full length cDNA of Pe GPX from P. e up hratica, and the Pe GPX gene was overexpressed into tobacco plants to analyze its contribution to salt tolerance. Blast analysis shows that the cloned cDNA encodes Glutathione peroxidase, which is a hydrophobic protein of 231 amino acids and has an ORF of 693 bp. Comparing salt tolerance of the overexpressed transgenic tobacco plants with that of the wild-type tobacco plants, both of which had been cultivated in MS medium supplemented with 200 mmol/L NaC1 for 15 days, the wild-type plants was almost as high as before and could not grow new roots, whilethe transgenic plants almost grew uninhibitedly and new roots were seen in the medium. The data of photosynthetic shows that the salt stress has less influence on the net photosynthetic rate of transgenic tobacco plants than that of wild-type plants. Meanwlalle, me tJrA enzyme activity of transgenic plants is much higher than that of wild-type tobacco under salt stress. This research reveals that overexpressed PeGPX gene could improve the capacity of salt tolerance in tobacco plants and it is significant for the further study on the function of PeGPX in the salt tolerance ofP. euphratica.